Brush-spring for dynamos and motors.



APPLICATION FILED MAR.19, 1907.

Patented Feb. 23, 190,

l/VVENIOR Joim' Hudson Poole B7 @01 6, Q aqflomm WITNESSES UNITED STATES PATENT OFFICE.

JOHN H. POOLE, OF WASHINGTON, DISTRICT OF COLUMBIA.

BRUSH-SPRING FOR DYNAMOS AND MOTORS.

Specification of Letters Patent.

Patented Feb. 23, 1909.

Application filed. March 19, 1907. I Serial No. 363,214.

T 0 all whom it may concern:

Be it known that I, J OHN HUDSON POOLE, a citizen of the United States, residing at Washington, in the District of Columbia, have invented a new and useful Brush- Spring for Dynamos and Motors, of which the following is a specification.

My .invention relates to commutator brushes for dynam'os or motors.

It particularly concerns commutator brushes of the type wherein the brush con sists of a bar of conducting material guided in a holder and pressed downward into con vents any bindin of the brush hol tact with the commutator by a curved steel spring bearing upon the top surface of the brush. I

The object of'the invention is to apply the pressure of the spring in such manner as to eep the brush in constant and intimate con-' tact with the commutator of the machine,

notwithstanding the vibration which may be setup by the machinc'when running at high speeds. According to my invention, this is accom lished by my special means for insuring app ication of the s ring pressure in a direction perfectly norma to the surface of the brush, thus preventing the brush from becoming cooked or bound against the sides of the brush holder.

ing drawings, wherein Figure 1 is a side elevation, partly in section, showing the brush holder broken away in vertical section. Fig. 2 is a front elevation of a brush holder, brush, and spring,

'with my invention applied thereto.

referably spring 5, on the extremity of whichis a yoke 6, provided with outside bearings 7, in which is yournaled a small steel roller 8. The me tallic plate 9 on the upper surface of the brush forms a truebearing surface at right angles to the front, rear, and sides of the brush. The roller 8 revolves freely in -the bearings 7, so thatthe pressure of the sprin transmitted to the brush is always norma to the top surface of the latter, and hence is applied in a direction exactly parallel to the si es and faces of said brus This preof the brush on the'sides er, and enables the brush I I r i l l l can'accomplish this ficulty, by the means illustrated in the accompanytends to bear centrally to take up the small shocks and jars transmitted to it by the commutator without becoming cooked or bound in the brush holder, thus avoiding sparking.

I am aware that prior to my invention carbon brushes and brush holders of the form shown herein have been used and also that curved steel springs have been used to hold such brushes against a commutator. In fact, my invention was the result of. practical use of a construction substantially such as is shown in the United States Patent to Erben 705,055, granted July 22nd, 1902. The construction therein disclosed includes a spring of such peculiar proportions that it rear end of the brush in all positions of wear of the latter, hence an antifriction roller at the end of said spring would appear to one skilled in the art as unnecessary and without useful function. I have discovered, howand evenly upon the ever, that in the case of high speed electric-..

machines, vibrations are set up which in certain cases cause wear between. the brush and its holder and between the spring and the end of the brush or cap covering the latter. It is not necessary to explain at length the precise functioning of this difit bein sufficient topoint out that.

as a matter of act such a spr1ng, even when carefully designed, may, and commonly does, transmit pressure having sufficient lateral component to cause the'brush to become cocked as herein above set forth.

This effect I have entirely remedied by the above simple expedient. 1 claim: v 1. A brush holder, abrush mounted for endwise movement curvedleaf spring, one end of which is suitably supported and the other end of which.

in said holder, and a.

bears upon a portion of the rear face of the 7 brush, in combination with an .antifriction roller arranged as the bearing surface -for said spring, whereby high speed vibrations may take effect as resilient lateral movements of said roller without transmittin 'to the brush of any lateral component 0 said movements.

2. A brush holder, a brush slidably' mounted therein, and a longitudinally curved sgring'flattened in a p e plane of curvature, spring being suitably su other end thereof norma y one end of said tends tob'ear on the same portion of the rear face of the orte'cl, so that the direction transverse to} v brush, in combination with an antifriction roller arranged as the bearing surface for said spring, whereby vibratory displacements from the normal hearing point may be corrected by resilient movement of said arm Without the transmission to the brush of any lateral component of said movement of vibratory displacement.

3. A holder and a resilient arm, one end of which is suitably supported and the other cud of which is maintained in bearing contact with the top of the brush by the resilient quality of said arm, in combination with an antifriction roller for the bearing surface of said arm, whereby said vibratory displacements of said bearing point may be corrected by resilient movement of said arm without the transmission to the brush of any lateral component of saidmovement of vibratory dis lacement. 5 4'. A brus holder, a brush slidably j mounted therein, and a fiat spring bearing against the rear face of said rushvby the resilient quality of said s ring, in combination with-a pan of outsi e bearin s and an antifriction steel roller mounte therein and forming the bearing surface for applying the pressure of said spring to said rear face of said brush, whereby vibratory displacements of the normal bearing point may be corrected by resilient 'movement of said spring without the transmission to the brush of any lateral component of the movements of vibratory displacements.

In witness whereof I have signed my name to this specification in the presence ofxtwo subscribing Witnesses.

J. H. POOLE.

' Witnesses: I

R. A. DELLETT,

ALEX. B. EADIE. 

